JP2001192629A - Adhesive tape and base material for adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive tape free from the generation of toxic gas attributable to burning during incineration and having excellent heat-deformation resistance and flame resistance (further, excellent extensibility), and an adhesive tape base material to be used in the adhesive tape. SOLUTION: The adhesive tape has a constitution in which the base material contains an olefinic polymer and an inorganic flame retardant, and is substantially free from a halogen atom. On at least one side of the base material, an adhesive layer is formed, and the adhesive tape has the ratio of heat deformation of <=65% at 100 deg.C and a breaking elongation of >=150% at a rate of pulling of 300 mm/min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive tape having flame retardancy and an adhesive tape base used for the adhesive tape.

[0002]

2. Description of the Related Art Conventionally, a tape base (hereinafter, simply referred to as a base) made of polyvinyl chloride (hereinafter, referred to as PVC).
Adhesive tapes made of are excellent in mechanical properties (especially flexibility and extensibility), flame retardancy, heat deformation resistance, electrical insulation, etc., and are relatively inexpensive, so they can be used in automobiles, trains, buses In addition to such vehicles, they have been used as insulating tapes for electric devices in various fields such as aircraft, ships, houses, factories and the like. In particular, adhesive tapes for binding and winding coils and electric wires of wire harnesses and electric home appliances used for electric wiring of automobiles and the like have high flame retardancy (oxygen index concentration is 25% or more) and heat deformation resistance. As needed, pressure-sensitive adhesive tapes based on PVC have been widely used to satisfy such requirements.

However, in recent years, environmental awareness has increased, and PVC has been restricted in use due to suspicion of the generation of harmful gases such as dioxin and chlorine gas when incinerated.
There is a move towards materials with less environmental impact. Therefore,
As an alternative to such PVC, the use of a polyolefin-based resin that does not generate harmful gases such as chlorine gas as a base material, even if incinerated, has been studied. Since the system resin has a drawback that it is more flammable than PVC, it is necessary to add a flame retardant. For example,
No. 10898 proposes to add an inorganic flame retardant such as magnesium hydroxide or aluminum hydroxide which has a low environmental load.

However, in consideration of the flexibility and elongation required for the adhesive tape, polypropylene or high-density polyethylene having a relatively high melting point is not suitable as a polyolefin-based resin. Polyethylene, ultra-low-density polyethylene, medium-density polyethylene, ethylene-vinyl acetate copolymer, low-melting polyolefin resin such as ethylene-ethyl acrylate copolymer must be used. It has the drawback that it is flexible and easily stretched, but easily deformed by heat.

As a method for improving the heat deformation resistance of the resin film, for example, a method of irradiating the film with ionizing radiation or a method of adding a crosslinking agent such as an organic peroxide such as dicumyl peroxide to the resin in advance. There is known a method in which a molded film is subjected to steam heating or the like to generate a crosslinked structure in the film. However, since these methods increase the number of production steps and increase the manufacturing cost,
Difficult for practical use. Further, as another method, a relatively high melting point polypropylene, ethylene-propylene copolymer, high-density polyethylene or the like and an elastomer comprising an ethylene-based copolymer (for example, EPM (ethylene-propylene copolymer rubber), EBR (Ethylene-butene rubber),
EPDM (ethylene-propylene-diene copolymer rubber)
) Has been considered, but when an inorganic flame retardant is added to the polymer mixture, the molded article is very hard and lacks flexibility under a room temperature atmosphere. In this case, the extensibility is significantly reduced, and furthermore, the heat deformation resistance cannot be sufficiently improved.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a pressure-sensitive adhesive tape which does not generate toxic gas due to combustion during incineration and has excellent heat-resistant deformation properties and flame retardancy. An object of the present invention is to provide an adhesive tape base material used for a tape. It is still another object of the present invention to provide a pressure-sensitive adhesive tape having excellent heat-deformability and flame retardancy, and excellent stretchability suitable for a tape winding operation, and a pressure-sensitive adhesive tape substrate used for the pressure-sensitive adhesive tape.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and as a result, as an olefin polymer, a thermoplastic resin having a carbonyl oxygen atom in a molecular skeleton, an ethylene component By using in combination with a polymer alloy containing a propylene component and mixing them with an inorganic flame retardant to form a tape base, while having high flame retardancy, it has high heat deformation resistance and extensibility. It has been found that an excellent pressure-sensitive adhesive tape substrate can be obtained, and the present invention has been completed. That is, the present invention has the following features.

(1) A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface of a substrate, wherein the substrate contains an olefin polymer and an inorganic flame retardant and contains substantially no halogen atoms. Yes, 10 of the adhesive tape
An adhesive tape having a heat deformation ratio at 65 ° C. of 65% or less. (2) The pressure-sensitive adhesive tape according to (1), wherein the pressure-sensitive adhesive tape has a breaking elongation at a tensile speed of 300 mm / min of 150% or more. (3) The olefin polymer constituting the base material is the following A
(1) or (2) above comprising a component and a B component.
The adhesive tape as described. A component: a thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton B component: a polymer alloy containing an ethylene component and a propylene component (4) The compounding weight ratio (A: B) of the A component and the B component is 1: 9.
To 8: 2, the pressure-sensitive adhesive tape according to the above (3). (5) The pressure-sensitive adhesive tape according to any one of (1) to (4), wherein the base material contains 20 to 200 parts by weight of an inorganic flame retardant per 100 parts by weight of the olefin-based polymer. (6) The pressure-sensitive adhesive tape according to any one of (1) to (5), wherein the inorganic flame retardant constituting the base material is a metal hydroxide. (7) The dynamic storage elastic modulus (E ′) at 80 ° C. of the pressure-sensitive adhesive tape is 25 MPa or more, and the dynamic storage elastic modulus (E ′) at 120 ° C. is 10 MPa or more. The adhesive tape according to any one of 6). (8) The above-mentioned (1) to (7), wherein the substrate is not subjected to a crosslinking treatment in the molding process and / or after the molding.
The adhesive tape according to any one of the above. (9) An adhesive tape base material containing an olefin polymer and an inorganic flame retardant and containing substantially no halogen atom, wherein the olefin polymer contains the following components A and B. Adhesive tape substrate. A component: a thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton B component: a polymer alloy containing an ethylene component and a propylene component (10) The compounding weight ratio (A: B) of the A component and the B component is 1:
The pressure-sensitive adhesive tape substrate according to the above (9), wherein the ratio is 9 to 8: 2. (11) The pressure-sensitive adhesive tape substrate according to the above (9) or (10), which contains 20 to 200 parts by weight of an inorganic flame retardant per 100 parts by weight of the olefin-based polymer. (12) The above (9), wherein the inorganic flame retardant is a metal hydroxide.
The pressure-sensitive adhesive tape substrate according to any one of (1) to (11). (13) Dynamic storage elastic modulus (E ′) at 80 ° C. of 25
(9) to (1) wherein the dynamic storage elastic modulus (E ′) at 120 ° C. is 10 MPa or more.
The pressure-sensitive adhesive tape substrate according to any one of 2). (14) The pressure-sensitive adhesive tape substrate according to any one of the above (9) to (13), wherein the substrate is not subjected to a crosslinking treatment in a molding process and / or after the molding.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The pressure-sensitive adhesive tape of the present invention comprises an olefin polymer and an inorganic flame retardant, and is provided with a pressure-sensitive adhesive layer on at least one surface of a tape base material substantially free of halogen atoms. The heat deformation of the pressure-sensitive adhesive tape at 100 ° C. shows 65% or less (preferably 40% or less, particularly preferably 0%), and shows the heat deformation of 65% or less and a tensile speed of 300 mm /
The elongation at break of the pressure-sensitive adhesive tape per minute is 150% or more (preferably 170 to 500%).

Here, "the tape base material does not substantially contain a halogen atom" means that a substance containing a halogen atom in a molecule is not used as a constituent material of the base material. For example, when a composition analysis of a tape base material is performed by an instrumental analysis means, a halogen atom detected at a trace level (for example, a halogen atom due to a halogen-containing substance used as a catalyst at the time of synthesis of a compound (constituent material) becomes a compound ( As a result of being mixed into the constituent material), the inclusion of a trace amount of halogen atoms detected from the base material) is allowed.
In addition, the heat deformation rate at 100 ° C. of the adhesive tape and the elongation at break (%) at a tensile speed of 300 mm / min are used as indices of heat deformation resistance and extensibility of the adhesive tape, respectively. Heat deformation rate is 6
Those showing 5% or less show sufficient heat deformation resistance in an actual use state (a state of being adhered to an object), and have an elongation at break of 15 mm at a tensile speed of 300 mm / min.
Those showing 0% or more can be easily stretched in an actual use state (at the time of sticking (wrapping) work to an object), and the sticking (wrapping) work can be performed with good workability. The heat deformation ratio and the elongation at break of the pressure-sensitive adhesive tape are values measured by the following methods.

[Heating Deformation Measuring Method] This method is performed according to UL-510. As shown in FIG. 1 (a), a test body 10 in which an adhesive tape T is wound around an outer peripheral surface of a round bar 1 made of a conductor having a diameter (d) of 2 mm and a length of 30 mm is prepared. The outer diameter (D ₀ ) of the test piece 10 at normal temperature is determined according to JIS B7503.
And a caliper specified in JIS B7507, or a measuring instrument having the same measurement accuracy as these. Next, the test piece 10 was heated to a specified temperature (1
(00 ° C. ± 1.0 ° C.) and heated for 60 minutes, and then the test piece was placed in a cylindrical convex portion 2a having a diameter of 9.5 ± 0.2 mm as shown in FIG. 1 (b). Is installed between the pressure plate 2 and the parallel plate 3 having a pressure, and pressurized (4.9 N) from a direction perpendicular to the plane of the plate, and furthermore, a specified temperature (100 ° C. ±
(1.0 ° C.) for 60 minutes, the outer diameter (D ₁ ) of the test specimen was measured as it was, and the thickness of the tape before heating (t ₀ ) and the thickness of the tape after heating (t ₀ ) ₁ ) by the following formula (I
I), and according to the following formula (III):
The reduction rate (heat deformation rate) (X) of the thickness of the tape after heating from the thickness of the tape before heating is calculated.

T = (D−d) / 2 (II) (where D is the outer diameter of the specimen, d is the diameter of the round bar)

X (%) = {(t ₀ −t ₁ ) / t ₀ } × 100 (III) (where, t ₀ is the thickness (mm) before heating, and t ₁ is the thickness after heating ( mm))

[Method of measuring elongation at break] A test piece (width 19 mm, length 100 mm) taken from a pressure-sensitive adhesive tape (a tape base material having a thickness of 0.2 mm and a pressure-sensitive adhesive layer having a thickness of 30 μm provided on one side of a tape base material) Under an atmosphere of 23 ° C. and 60% RH at both ends in the length direction of the test piece (where the length direction is applied in the molding flow direction (MD direction) of the tape base material). Using a universal tensile and compression tester, tensile speed: 300
mm / min, pulling the test piece in the length direction,
The elongation at break (%) is measured.

In the present invention, the olefin-based polymer constituting the tape substrate is mixed with an inorganic flame-retardant in such an amount that sufficient flame-retardancy can be obtained. And any one that can impart elongation can be used without particular limitation.
Those mainly composed of the component and the component B are preferred. A component: a thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton B component: a polymer alloy containing an ethylene component and a propylene component

The thermoplastic resin having a carbonyl oxygen atom (oxygen atom belonging to a carbonyl group) in the molecular skeleton of the component A mainly activates the action of imparting flame retardancy by the inorganic flame retardant, and at the same time, activates the tape base. Material (adhesive tape)
In particular, a soft polyolefin-based resin having a carbonyl oxygen atom in the molecular skeleton is suitable. Examples of the soft polyolefin resin having a carbonyl oxygen atom in the molecular skeleton include an ethylene copolymer obtained by using a vinyl ester compound and / or an α, β-unsaturated carboxylic acid or a derivative thereof as a monomer or a comonomer. Or a metal salt thereof (ionomer), and generally has a melting point of 120 ° C. or less, preferably 40 to 1
00 ° C. Here, the melting point is indicated by a differential scanning calorimeter (DSC).
It is a measured value by.

Examples of the vinyl ester compound in the ethylene copolymer or its metal salt (ionomer) include lower alkyl esters of vinyl alcohol such as vinyl acetate. Examples of the α, β-unsaturated carboxylic acid or a derivative thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, and itaconic anhydride, and anhydrides thereof; Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate , Stearyl acrylate, stearyl methacrylate, lauryl acrylate, lauryl methacrylate, monomethyl maleate,
Monoethyl maleate, diethyl maleate, monomethyl fumarate, glycidyl acrylate, unsaturated carboxylic esters such as glycidyl methacrylate and the like, among which alkyl (meth) acrylates are preferred, Particularly preferred is ethyl acrylate.

Preferable specific examples of the ethylene copolymer or its metal salt (ionomer) include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene- Acrylic acid-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate-ethyl acrylate copolymer And a metal salt (ionomer) thereof, and one or more of these are used.

The effect of activating the effect of imparting the flame retardancy of the inorganic flame retardant by the thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton of the component A is due to the fact that the carbonyl oxygen atom is also present in the molecular skeleton. It cannot be obtained with unsatisfactory thermoplastic resins.

The polymer alloy containing the ethylene component and the propylene component of the B component is a component for mainly suppressing the thermal deformation of the tape base (adhesive tape), and by alloying two or more polymers, In particular, it is a polymer alloy exhibiting viscoelasticity suitable for suppressing thermal deformation of a tape substrate (adhesive tape).

The configuration (form) of the polymer alloy is not particularly limited. For example, a polymer blend in which two or more polymers are physically mixed (a physical mixture), and two or more polymers are covalently bonded. An IPN (Interpenetrati) in which a bonded block copolymer or graft copolymer and two or more polymers are entangled without being covalently bonded to each other.
ng Polymer Network) various structures (forms)
Are acceptable. Further, the polymer alloy is not necessarily compositionally uniform (it may have a distribution), and even if two or more polymers are compatible (compatible polymer alloy), two or more polymers may be used. May be incompatible and form a phase-separated structure (incompatible polymer alloy). Further, it may have thermal characteristics such as having a plurality of exothermic or endothermic peaks by DSC measurement.

As the polymer alloy containing the ethylene component and the propylene component of the component B, for example, polypropylene (homopolypropylene, random polypropylene)
Mixtures of propylene with polyethylene (including copolymers of ethylene and a small amount of α-olefin), propylene / ethylene copolymers, terpolymers of propylene with ethylene and other α-olefins (Examples of other α-olefins include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like, with 1-butene being preferred). No. Here, “homopolypropylene” means a polymer substantially composed of 100% polypropylene, and “random polypropylene” means a polymer obtained by randomly copolymerizing several percent of ethylene components.

When the polymer alloy is a copolymer, a copolymer obtained by multi-stage polymerization of two or more stages is preferable,
Further, a propylene / ethylene copolymer is preferred. The copolymer polymerized by the multi-stage polymerization of two or more stages,
Specifically, as described in JP-A-4-224809, for example, in the presence of a titanium compound and an organoaluminum compound catalyst, first, propylene or propylene and an α-olefin other than propylene are subjected to multistage polymerization. Preliminary polymerization is performed in the first stage, and then, in the second and subsequent stages, propylene and ethylene are copolymerized in the presence of the produced titanium-containing polyolefin and the organoaluminum compound (if necessary, other than propylene and ethylene. α-olefin is further added for copolymerization). Thereby, the polymer (for example, polypropylene (propylene homopolymer), propylene-α-olefin copolymer, etc.) generated in the first stage
And the polymer (for example, propylene-ethylene copolymer, propylene-ethylene-other α-olefin copolymer, etc.) produced in the second and subsequent stages, And the copolymer is blended.
Examples of the titanium compound include spherical particles obtained by co-pulverizing titanium trichloride and magnesium chloride and treating them with n-butyl orthotitanate, 2-ethyl-hexanol, ethyl p-toluate, silicon tetrachloride, diisobutyl phthalate, or the like. For example, a solid catalyst having an average particle diameter of 15 μm is used. As the organoaluminum compound, for example, an alkylaluminum such as triethylaluminum is used.
In the polymerization layer, a silicon compound such as diphenyldimethoxysilane is added as an electron donor,
An iodine compound such as ethyl iodide may be added.

The polymer alloy containing the ethylene component and the propylene component of the component B exhibits high elasticity at a high temperature, that is, considering the temperature at the time of using an adhesive tape,
The dynamic storage modulus (E ') at 80 ° C is 40MP
a or more and less than 180 MPa (preferably 45 to 160 M
Pa) and a dynamic storage modulus (E ′) at 120 ° C. of 12 MPa or more and less than 70 MPa (preferably within a range of 15 to 65 MPa). By exhibiting such a dynamic storage modulus (E '), thermal deformation of the tape substrate (adhesive tape) is sufficiently suppressed. The dynamic storage elastic modulus (E ′) here was obtained by preparing a test piece (thickness 0.2 mm: width 10 mm, length 20 mm) of a polymer alloy, and calculating the dynamic viscoelastic behavior of the test piece by temperature dispersion. Using a DMS200 (trade name, manufactured by Seiko Instruments Inc.) as a measuring instrument, the value is a value measured under the following measuring conditions: measuring method: tension mode, heating rate: 2 ° C./min, frequency: 1 Hz.

Specific examples of the polymer alloy exhibiting such a dynamic storage elastic modulus (E ') include, for example, Cataloy K (trade name, manufactured by Montell SDK Sunrise Co., Ltd.).
S-353P, Cataloy KS-021P, Cataloy C200F and the like.

In consideration of the workability of the pressure-sensitive adhesive tape near room temperature (the ability of the pressure-sensitive adhesive tape to adhere to an object to be adhered), the polymer alloy of the component B has a dynamic storage modulus (E ′) at 23 ° C. ) Is preferably 200 MPa or more and less than 400 MPa. When the polymer alloy of the component B has such a dynamic storage modulus (E ′), the tape base material has good flexibility, and the followability to the adherend is improved. The dynamic storage elastic modulus (E ') is a value measured by the above-mentioned method, and specific examples of the polymer alloy exhibiting the dynamic storage elastic modulus (E') include, for example, Montel SD Product names Cataloy KS-353P and Cataloy KS-0 manufactured by Kei Sunrise Co., Ltd.
21P, Cataloy C200F and the like.

The compounding weight ratio (A: B) of the component A (a thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton) and the component B (a polymer alloy containing an ethylene component and a propylene component) is usually from 1: 9 to 1: 9. 8: 2, preferably 2: 8-
6: 4. If the weight ratio deviates from this ratio and the amount of the A component is small (the amount of the B component is large), the extensibility and the flame retardancy of the tape base may be reduced. , There is a possibility that heat deformation resistance may decrease.

In the present invention, the inorganic flame retardant includes
For example, metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide and barium hydroxide; metal carbonates such as basic magnesium carbonate, magnesium-calcium carbonate, calcium carbonate, barium carbonate and dolomite ; Hydrotalcite,
Metal hydrates such as borax (hydrates of metal compounds); barium metaborate, magnesium oxide and the like. These may be used alone or in combination of two or more. Among them, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, metal hydroxides such as barium hydroxide, and basic magnesium carbonate, those selected from the group consisting of hydrotalcite, flame retardant It is excellent in giving effect and economically advantageous.

The particle size of the inorganic flame retardant varies depending on the kind of the compound. For example, in the case of metal hydroxides such as aluminum hydroxide and magnesium hydroxide, the average particle size is 0.1 to 50 μm, preferably A particle size of about 0.5 to 20 μm is appropriate. The particle size here is a particle size measured by a laser diffraction method.

The amount of the inorganic flame retardant is usually 20 to 200 parts by weight, preferably 40 to 150 parts by weight, per 100 parts by weight of the olefin polymer. When the amount of the inorganic flame retardant is less than the above range, it is difficult to impart sufficient flame retardancy to the tape base (adhesive tape). The flexibility and elongation tend to decrease.

Red phosphorus may be used for the purpose of promoting the char (carbonized layer) of the inorganic flame retardant. When using red phosphorus, red phosphorus is converted to aluminum hydroxide, magnesium hydroxide, zinc hydroxide, Use a material coated with a metal hydroxide film selected from titanium, or provide a thermosetting resin (phenolic resin, etc.) coating on the metal hydroxide film and double coat It is preferred to use the treated one. Such a char-forming auxiliary containing red phosphorus is usually used in an amount of 2 to 100 parts by weight of the olefin-based polymer.
It is appropriate to use 10 parts by weight, preferably 4 to 8 parts by weight.

When a char-forming aid containing red phosphorus is used, at least one selected from the group consisting of carbon black, borate and a silicone compound (silicone oil, silicone rubber, silicone resin, etc.) can be used in combination. Good results can be obtained. In this case, it is appropriate that at least one selected from carbon black, borate and silicone compound is used in an amount of usually 0.5 to 10% by weight, preferably 1 to 5% by weight, per 100 parts by weight of the olefin-based polymer.

In the present invention, the tape base material comprises an olefin polymer and an inorganic flame retardant as essential components. If necessary, an inorganic filler such as titanium oxide and zinc oxide, an amine-based resin, a quinoline Antioxidants, antioxidants, salicylic acid derivatives, benzophenones, benzotriazoles, hindered amines, etc. UV absorbers, lubricants, plasticizers, etc. You may mix.

In the present invention, the tape base material is usually dry-blended with a polyolefin-based polymer and an inorganic-based flame retardant (and optionally blended materials such as fillers), and the mixture is mixed with a Banbury mixer, a roll, It is obtained by kneading using an extruder or the like, and forming the kneaded product into a film by a known forming method such as compression molding, calendar molding, injection molding, or extrusion molding. The thickness of the tape substrate (film) varies depending on the use of the adhesive tape, but is generally 0.01 to 1 mm, preferably 0.01 mm.
5 to 0.5 mm.

The tape base material of the present invention may be subjected to a crosslinking treatment of irradiating an ionizing radiation such as an electron beam, a β-ray or a γ-ray after the film is formed, or a crosslinking of an organic peroxide or the like in the film forming material. It is preferable not to carry out a crosslinking treatment in the molding process by adding an agent or a crosslinking assistant. That is, it is preferable that the crosslinked structure is not formed on the entire substrate.

The pressure-sensitive adhesive tape of the present invention is constituted by providing a pressure-sensitive adhesive layer on at least one surface of the tape base material. As the pressure-sensitive adhesive, all existing pressure-sensitive adhesives such as rubber-based, hot-melt-based, acrylic-based, and emulsion-based adhesives can be used. Examples of base polymers for rubber-based and hot-melt-based pressure-sensitive adhesives include natural rubber, recycled rubber, silicone rubber, isoprene rubber, styrene-butadiene rubber, polyisoprene, NBR, styrene-isoprene copolymer, and styrene-isoprene-butadiene copolymer. Are preferred.

Examples of the tackifier used for the adhesive include rosin-based tackifiers, terpene-based tackifiers, aliphatic petroleum hydrocarbon (C ₅ ) -based tackifiers,
Examples thereof include aliphatic petroleum hydrocarbon (C ₉ ) -based tackifiers and hydrogenated compounds. Further, additives such as oil, wax, antioxidant and the like generally added to the adhesive of the adhesive tape may be added. When these are added, the amounts added are determined according to a conventional method.

Among the above-mentioned pressure-sensitive adhesives, an acrylic pressure-sensitive adhesive is preferable, and examples of the acrylic pressure-sensitive adhesive include homopolymers of (meth) acrylic acid esters and copolymers with copolymerizable monomers. Examples of the (meth) acrylate or the copolymerizable monomer include alkyl (meth) acrylates (eg, methyl ester, ethyl ester, butyl ester, 2-ethylhexyl ester, octyl ester, etc.) and glycidyl (meth) acrylate. , (Meth) acrylic acid, itaconic acid, maleic anhydride, (meth) acrylic acid amide, (meth) acrylic acid N-hydroxyamide, (meth) acrylic acid alkylaminoalkyl ester (for example, dimethylaminoethyl methacrylate, t- Butylaminoethyl methacrylate), vinyl acetate, styrene, acrylonitrile and the like. Among these, as the main monomer, an alkyl acrylate ester whose homopolymer (homopolymer) usually has a glass transition temperature of -50 ° C or lower is preferable.

As a method of applying the pressure-sensitive adhesive, a conventionally known method can be used, and for example, a casting method, a roll coater method, a reverse coater method, a doctor blade method, and the like can be used.

The thickness of the pressure-sensitive adhesive layer (thickness after drying) varies depending on the use of the pressure-sensitive adhesive tape, but is generally 10 to 50 μm.
m, preferably 15 to 40 μm.

In the present invention, the pressure-sensitive adhesive tape has a dynamic storage elastic modulus (E ′) at 80 ° C. of 25 MPa or more and a pressure of 120 ° C.
It is preferable that the storage elastic modulus (E ') is 10 MPa or more. By having such dynamic viscoelasticity, thermal deformation of the tape substrate (adhesive tape) is extremely unlikely to occur. The dynamic storage elastic modulus (E ′) at 80 ° C. is 200 from the viewpoint of appropriate flexibility and elongation required for the adhesive tape.
The dynamic storage elastic modulus (E ′) at 120 ° C. is preferably 150 MPa or less. The dynamic storage elastic modulus (E ') of the pressure-sensitive adhesive tape was determined by preparing a test piece (width 10 mm, length 20 mm) from a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer provided on a tape substrate having a thickness of 0.2 mm. The dynamic viscoelastic behavior due to the temperature dispersion of the piece was measured using DMS200 (trade name, manufactured by Seiko Instruments Inc.) as a measuring device under the following measuring conditions: tensile mode, heating rate: 2 ° C./min, frequency: 1 Hz. Value.

The dynamic storage elastic modulus (E ') of the pressure-sensitive adhesive tape has almost no effect on the value of the pressure-sensitive adhesive layer (that is, the dynamic storage modulus (E') depends on whether the pressure-sensitive adhesive layer has the pressure-sensitive adhesive layer or the tape base material alone). The value of the dynamic storage modulus (E ') does not change.), Which is substantially the dynamic storage modulus (E') of the tape substrate.

[0043]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Materials Used] Component A (having a carbonyl oxygen atom in the molecular skeleton )
Thermoplastic resin) A1: Ethylene-vinyl acetate copolymer (EVA), melting point 84 ° C. [trade name: Evaflex P-1905, manufactured by DuPont-Mitsui Polychemicals Co., Ltd.] A2: Ethylene-ethyl acrylate copolymer ( EE
A), melting point 84 ° C. [trade name: Evaflex A-70]
2, made by Mitsui Dupont Polychemical Co., Ltd.]

B component (ethylene component and propylene component
Polymer alloy) B1, including: CATALLOY KS-353P (trade name), Montell S. Dee Kay Sunrise Co., Ltd. B2: CATALLOY KS-021P (trade name), Montell S. Dee Kay Sunrise Co., Ltd. B3: CATALLOY C200F (Trade name), manufactured by Montell SDK Sunrise Co., Ltd.

23 ° C., 80 ° C., 120
The dynamic storage modulus at ° C. is as follows. B1 (23 ° C .: 210 MPa, 80 ° C .: 52 MPa, 1
20 ° C .: 21 MPa) B2 (23 ° C .: 294 MPa, 80 ° C .: 125 MPa,
120 ° C .: 59 MPa) B3 (23 ° C .: 303 MPa, 80 ° C .: 65 MPa, 1)
20 ° C: 20 MPa)

C component (inorganic flame retardant) C1: magnesium hydroxide (Mg (OH) ₂ ) [trade name: Magseeds N-3 manufactured by Kamishima Chemical Industry Co., Ltd.] C2-1: red phosphorus [trade name: Hishigard] CP-A15
Nippon Kagaku Kogyo Co., Ltd.] C2-2: Red phosphorus [Trade name: Nova Excel F5 Rin Kagaku Kogyo Co., Ltd.] C3: Carbon black [Trade name: Seast 3H Tokai Carbon Co., Ltd.]

[Method of Making Tape Base and Adhesive Tape]
The components A, B and C are dry-blended and then kneaded at 180 ° C. in a 3 L pressure kneader to form pellets. The composition was formed into a film having a thickness of 0.2 mm by a T-die extruder to prepare a tape base material, and a corona discharge treatment was applied to one surface of the tape base material. An adhesive tape is prepared by applying a system adhesive (thickness: 30 μm).

[Method for Preparing Acrylic Pressure-Sensitive Adhesive]
A reaction vessel equipped with a nitrogen inlet tube, a thermometer and a stirrer was charged with 2-ethylhexyl acrylate 100 in toluene solvent.
Parts by weight, 2 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator were added and reacted at 60 ° C. for 8 hours to obtain a polymer. To this polymer solution, 3 parts by weight of a polyisocyanate-based crosslinking agent (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by weight of the polymer solid content to prepare an acrylic pressure-sensitive adhesive.

(Examples 1 to 7) A component, B component and C component
The components were the materials and amounts shown in Table 1 below, and a tape substrate (adhesive tape) was prepared in accordance with the above-described preparation method.

Comparative Example 1 A tape base (adhesive tape) was used in accordance with the above-mentioned method for producing a tape base (adhesive tape), except that component A (A1: 100 parts by weight) was used, component B and component C were not used. Tape).

(Comparative Example 2) A component (A2: 100 parts by weight) was used, components B and C were not used. Tape).

Comparative Example 3 A tape base material (adhesive tape) was used in accordance with the above-described method for producing a tape base material (adhesive tape), except that component B (B1: 100 parts by weight) was used, component A and component C were not used. Tape).

(Comparative Example 4) A component, B component and C component were not used, and 100 parts by weight of polypropylene (PP) [trade name: Novatec FX3 manufactured by Nippon Polychem Co., Ltd.] was used. A tape base material (adhesive tape) was prepared according to a method for preparing a material (adhesive tape).

(Comparative Example 5) Preparation of the above tape base material (adhesive tape) using component A (A1: 100 parts by weight) and component C (C1: 50 parts by weight) without using component B A tape substrate (adhesive tape) was prepared according to the method.

(Comparative Example 6) Preparation of the above tape base material (adhesive tape) using component A (A1: 100 parts by weight) and component C (C1: 100 parts by weight), not using component B, and otherwise A tape substrate (adhesive tape) was prepared according to the method.

(Comparative Example 7) A component (A1: 100 parts by weight) and a C component (C1: 105 parts by weight, C2-1: 5 parts by weight) were used, the B component was not used, and the other tapes were the above. A tape substrate (adhesive tape) was prepared according to the method of preparing a substrate (adhesive tape).

Comparative Example 8 A component (A1: 100 parts by weight), C component (C1: 50 parts by weight, C2-2: 4 parts by weight, C3: 2 parts by weight) were used, and B component was not used. Others prepared a tape base (adhesive tape) in accordance with the above-described method for preparing a tape base (adhesive tape).

(Comparative Example 9) Component A (A1: 50 parts by weight), Component C (C1: 100 parts by weight, C3: 2 parts by weight), polypropylene (PP) [Product name: Novatec F
X3 Nippon Polychem Co., Ltd.] 15 parts by weight, ethylene-
Propylene rubber (EPR) [trade name: SPO VO-1
41 manufactured by Sumitomo Chemical Co., Ltd.]
The components were not used, and a tape substrate (adhesive tape) was prepared according to the above-mentioned method for producing a tape substrate (adhesive tape).

[Evaluation Test] Examples 1 to 7 and Comparative Example 1
The following evaluation tests were performed on each of the tape bases (pressure-sensitive adhesive tapes) Nos. To 9. In addition, the dynamic storage elastic modulus (E ') at 80 ° C and 120 ° C of the pressure-sensitive adhesive tape was measured by the above-described method.

Evaluation of Flame Retardancy At the stage when the tape base was formed into a sheet having a thickness of 3 mm by a press machine, a test piece (dimensions: length 70 mm, width 6.5 mm) was collected from the sheet. , This test piece is J
The specimen is burned in accordance with the combustion test method of a polymer material by the oxygen index method of IS K7201, and the burning time of the test piece is continuously burned for 3 minutes or more, or the burning length after burning is 50 minutes.
The minimum flow rate of oxygen necessary to keep burning for more than 1 mm and the flow rate of nitrogen at that time are measured with a flow meter (device name "candle combustion tester"
The oxygen index was determined by the following formula (I), and the flame retardancy was evaluated using the oxygen index. 25
% Or more was judged as acceptable, and less than 25% was judged as failed.

Oxygen index (OI) = {[O ₂ ] / ([O ₂ ] + [N ₂ ])} × 100 (I)

(Where [O ₂ ] is the oxygen flow rate (l / mi)
n) and [N ₂ ] are nitrogen flow rates (l / min). )

Evaluation of heat deformation resistance and elongation The heat deformation resistance of the pressure-sensitive adhesive tape was measured by the above-mentioned method. The elongation was determined by measuring the elongation at break of the pressure-sensitive adhesive tape by the above-mentioned method, and the elongation at break was 150% or more.

The evaluation results and the pressure-sensitive adhesive tape at 80 ° C.
The dynamic storage modulus (E ′) at 120 ° C. is shown in Table 1 below.

[0066]

[Table 1]

In the table, the amounts of the components A, B and C are in parts by weight. In addition, * means that the dynamic storage elastic modulus (E ') could not be measured because the adhesive tape (substrate) was melted. The heat deformation rate of 100% means that the pressure-sensitive adhesive tape melted and flowed down from the round bar, and the tape form could not be maintained. Polypropylene (PP) and ethylene-propylene rubber (E) used in Comparative Examples 4 and 9
PR) is described in the column of B component for convenience.

[0068]

As is apparent from the above description, according to the present invention, the pressure-sensitive adhesive tape substrate contains an olefin polymer and an inorganic flame retardant and contains substantially no halogen atoms. The heat-deformation rate of the adhesive tape at 100 ° C. is 65% or less, and the tensile speed is 300 mm.
When the elongation at break (%) per minute is 150% or more, it has moderate flexibility, excellent elongation and heat-resistant deformation while containing an inorganic flame retardant. It is possible to obtain an adhesive tape that exhibits flame retardancy and does not generate toxic gases such as dioxin and halogen-based gas during incineration. The pressure-sensitive adhesive tape is, for example, a substitute for a pressure-sensitive adhesive tape using a PVC substrate, which has conventionally been used as an insulating tape for electric devices in various fields such as vehicles such as automobiles, trains, and buses, aircraft, ships, houses, factories, and the like. Since it can be used sufficiently, and there is no generation of toxic gas at the time of incineration, the load on the environment is small and its utility value is extremely high.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of an evaluation test method for evaluating a heat deformation rate of an adhesive tape, in which (a) is a side view of a test body, and (b) is a side view of a test apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Round bar 2 Pressure plate 2a Convex part 3 Parallel plate 10 Specimen T Adhesive tape

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) C08L 23/26 C08L 23/26 (72) Inventor Masayoshi Natsume 1-2-1, Shimohozumi, Ibaraki-shi, Osaka No. Nitto Denko Corporation (72) Shinichi Takada, Inventor 1-1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (72) Takaki Oyama 1-1-2, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation (72) Inventor ▼ Yanagi ▲ Ichi Taichi 1-2-1 Shimohozumi, Ibaraki-shi, Osaka F-term in Nitto Denko Corporation (reference) AB27 AE07 AF20Y AF21Y AF45Y AF47 AF54Y AH19 BB04 BB05 BB06 BC01 BC12 4J002 BB03Y BB05Y BB06W BB07W BB08W BB09W BB12X BB14X BB15X BB15Y BB23W CD19W DA056 DE066 DE076 DE096 DE146 E236 DE266 DE286 DK006 FB076 FB266 FD010 FD020 FD030 FD050 FD070 FD136 FD170 4J004 CA04 CC02 FA05

Claims (14)

[Claims] 1. A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface of a substrate, wherein the substrate contains an olefin-based polymer and an inorganic flame-retardant and contains substantially no halogen atoms. , 100 ° C of the adhesive tape
3. The pressure-sensitive adhesive tape according to claim 1, wherein the heat deformation ratio is 65% or less. 2. The adhesive tape has a tensile speed of 300 mm /
The pressure-sensitive adhesive tape according to claim 1, wherein the elongation at break in minutes is 150% or more. 3. The pressure-sensitive adhesive tape according to claim 1, wherein the olefin polymer constituting the base material contains the following components A and B. A component: a thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton B component: a polymer alloy containing an ethylene component and a propylene component 4. A compounding weight ratio of A component and B component (A: B)
Is a ratio of 1: 9 to 8: 2. 5. The pressure-sensitive adhesive tape according to claim 1, wherein the base material contains 20 to 200 parts by weight of an inorganic flame retardant per 100 parts by weight of the olefin-based polymer. 6. The pressure-sensitive adhesive tape according to claim 1, wherein the inorganic flame retardant constituting the substrate is a metal hydroxide. 7. The adhesive tape has a dynamic storage modulus (E ′) at 80 ° C. of 25 MPa or more, and
The pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein a dynamic storage modulus (E ') at 0 ° C is 10 MPa or more. 8. The substrate according to claim 1, wherein the substrate is not subjected to a crosslinking treatment during and / or after the molding.
8. The pressure-sensitive adhesive tape according to any one of 7. 9. A pressure-sensitive adhesive tape substrate containing an olefin polymer and an inorganic flame retardant and containing substantially no halogen atoms, wherein the olefin polymer contains the following components A and B: An adhesive tape base material characterized by the following. A component: a thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton B component: a polymer alloy containing an ethylene component and a propylene component 10. The compounding weight ratio of the component A and the component B (A:
The pressure-sensitive adhesive tape substrate according to claim 9, wherein B) is from 1: 9 to 8: 2. 11. The pressure-sensitive adhesive tape base according to claim 9, wherein the base material contains 20 to 200 parts by weight of an inorganic flame retardant per 100 parts by weight of the olefin-based polymer. 12. The pressure-sensitive adhesive tape substrate according to claim 9, wherein the inorganic flame retardant is a metal hydroxide. 13. The dynamic storage elastic modulus (E ′) at 80 ° C. is 25 MPa or more, and the dynamic storage elastic modulus (E ′) at 120 ° C. is 10 MPa or more. The adhesive tape base material according to 1. 14. The pressure-sensitive adhesive tape substrate according to claim 9, wherein the substrate is not subjected to a crosslinking treatment in a molding process and / or after the molding.